Knowledge of phosphorus compared with other nutrients in maintenance dialysis patients.

OBJECTIVE: This study's objective was to assess knowledge of phosphorus compared with other nutrients in patients undergoing maintenance dialysis (MD). DESIGN: We compared knowledge of phosphorus vs. other nutrients important to the MD diet (potassium, sodium, and protein) in patients undergoing hemodialysis (HD) and peritoneal dialysis (PD). We further measured gender, age, education level, and functional health literacy to assess correlations in patient nutrient knowledge. Nutrient knowledge was measured using a 25-item Chronic Kidney Disease Knowledge Assessment Tool for Nutrition (CKDKAT-N), and functional health literacy was measured using the short form of the Test of Functional Health Literacy in Adults (S-TOFHLA). SETTING AND PATIENTS: Patients received maintenance outpatient PD or HD at Wisconsin Dialysis, Inc. (Madison, WI). MAIN OUTCOME MEASURE: The main outcome measure was knowledge of phosphorus vs. knowledge of potassium, sodium, and protein. RESULTS: Forty-seven MD patients participated in the study (29 undergoing HD, 18 undergoing PD, 30 males, 17 females, average age of 58.6 (SD, 13.8) years, and average grade level of 1.4 (SD, 2.6) years of post-secondary education). Thirty-five participants had adequate health literacy, 4 had marginal health literacy, and 8 had inadequate health literacy. The CKDKAT-N scores ranged from 6-21 for 25 items, with a mean score of 13 (SD, 2.91). Knowledge of phosphorus compared with knowledge of other nutrients was poor (0.38 vs. 0.72, P = .003). In a comparison of HD vs. PD patient knowledge, both phosphorus (0.37 vs. 0.42, P = .231) and other nutrients (0.69 vs. 0.80, P = .115) were the same. CONCLUSION: Despite regular dietary instruction, patients undergoing MD have a poor knowledge of dietary phosphorus content, compared with knowledge of other nutrients important in chronic kidney disease. Interestingly, there was no difference in nutrition knowledge when comparing PD and HD patients, despite differences in education level and health literacy between groups.     

Effect of training frequency and specificity on isometric lumbar extension strength

To investigate the effects of training frequency and specificity of training on isolated lumbar extension strength, 72 men (age = 31 +/- 9 years) and 42 women (age = 28 +/- 9 years) were tested before and after 12 weeks of training. Each test involved the measurement of maximum voluntary isometric torque at 72 degrees, 60 degrees, 48 degrees, 36 degrees, 24 degrees, 12 degrees, and 0 degrees of lumbar flexion. After the pretraining tests, subjects were randomly stratified to groups that trained with variable resistance dynamic exercise every other week (1X/2 weeks, n = 19), once per week (1X/week, n = 22), twice per week (2X/week, n = 23) or three times per week (3X/week, n = 21); a group that trained isometrically once per week (n = 14); or a control group that did not train (n = 15). Analysis of covariance showed that all training groups improved their ability to generate isometric torque at each angle measured when compared with controls (P less than 0.05). There was no statistical difference in adjusted posttraining isometric torques among the groups that trained (P greater than 0.05), but dynamic training weight increased to a lesser extent (P less than 0.08) for the 1X/2 weeks group (26.6%) than for the groups that trained 1X/week, 2X/week, and 3X/week (37.2 to 41.4%). These data indicate that a training frequency as low as 1X/week provides an effective training stimulus for the development of lumbar extension strength. Improvements in strength noted after isometric training suggest that isometric exercise provides an effective alternative for developing lumbar strength.     

Invited commentary

World Journal of Surgery -     

Formaldehyde in cryoprotectant propanediol and effect on mouse zygotes

Cryopreservation of human zygotes and embryos has been routinely performed by in-vitro fertilization clinics for many years. Karran and Legge (1996) first reported that formaldehyde (FA) present in the cryoprotective solutions can have a deleterious effect on mouse oocytes. FA is a cytotoxic, carcinogenic and mutagenic chemical. The effect of FA on mouse zygotes was investigated. In addition, the concentrations of FA in propanediol (PROH) obtained from various sources were determined. Pooled 1-cell embryos were dispensed into droplets of modified Ham's F10 or human tubal fluid containing various concentrations of FA. Since bovine serum albumin (BSA) may minimize toxicity additional trials were done as above in the absence of BSA. FA concentration in the standard 1.5 M PROH, from different sources in water, was measured in the same assay using a standard curve of 0-100 microM FA. FA in a complex medium had a significant deleterious effect on embryo development and hatching but only at 1 mM concentration (P < 0.000001; see Tables I-III). There was no significant effect of FA at 100 microM. However, in a simple medium even 50 microM FA decreased embryo hatching. FA was present in 1.5 M PROH from different sources (range 1.0-35.3 microM concentration). It appears that FA concentrations do not increase with storage because FA concentrations were low even after opening and storage for 3 years on the shelf. This suggests that FA is a contaminant during the manufacturing process and may vary from manufacturer to manufacturer and batch to batch. Until further studies are done to confirm the lack of toxicity to embryos during cryopreservation (with or without FA scavengers) it may be prudent to screen all batches of cryoprotectants for FA as part of quality control.